this watch is a vintage Universal Genève $20 Gold Coin Watch, a prestigious collector's piece that integrates a high-grade Swiss movement inside an authentic 1894 United States $20 Liberty Head "Double Eagle" gold coin. Technical Details Materials: The case is an authentic U.S. gold coin (typically 21.6k or .900 fine gold), while the inner watch housing and integrated mesh bracelet are usually 18k Yellow Gold. Movement: Most versions of this "Coin Watch" use a high-quality, ultra-thin manual-winding movement (mechanical). Design: The watch face is typically concealed beneath a hinged cover—in this case, the obverse of the 1894 Liberty coin.